/*
 * Anything: A flexible and easy to use data structure that combines the 
 * characteristics of a list and a hashmap into one data structure.
 * 
 * Based on a paper by Peter Sommerlad and Marcel Rueedi on 
 * 'Do-it-yourself reflection' entered at EuroPLOP 1998.
 * 
 * This library was written completely from scratch and is based only 
 * in spirit on the original Java Anything implementation written by 
 * Andre Weinand/Marcel Rueedi in 1997/99 and enhanced by Stefan Tramm 
 * in 2006.
 * 
 * Copyright (c) 2008 Thomas Marti and others. All rights reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package any.impl.util;

import java.math.BigDecimal;

import static any.impl.util.NumberUtils.getBigDecimal;
import static any.impl.util.NumberUtils.isSpecialNumber;

public class NumberUtils {
	
	public static BigDecimal getBigDecimal(Number number) throws IllegalArgumentException {
		checkNotSpecialNumber(number);
		if (number == null) {
			return null;
		} else if (number instanceof BigDecimal) {
			return (BigDecimal)number;
		} else {
			return new BigDecimal(number.toString()).stripTrailingZeros();
		}
	}

	public static void checkNotSpecialNumber(Number number) throws IllegalArgumentException {
		if (number != null && isSpecialNumber(number)) {
			throw new IllegalArgumentException("NaN and Infinites not allowed, was: " + number);
		}
	}
	
	public static boolean isSpecialNumber(Number number) {
		if (number == null) {
			return false;
		} else {
			return (Double.isInfinite(number.doubleValue()) || Double.isNaN(number.doubleValue()));
		}
	}
	
	public static Number getNativeNumber(Number number) {
		assert !isSpecialNumber(number);
		
		if (Utils.isInstanceOf(number, Byte.class, Short.class, Integer.class)) {
			return number.longValue();
		}
		
		BigDecimal bd = getBigDecimal(number);

		try {
			return bd.longValueExact();
		} catch (ArithmeticException e) {}
		
		try {
			return bd.toBigIntegerExact();
		} catch (ArithmeticException e) {}
		
	    return bd;
    }
}
